To investigate the effect of 10,600 nm CO2 laser combined with Zimmer Cryo 6 forced cold air device on the comfort and efficacy of patients with burn scars or post-operative linear scars, and to provide a safer, more effective and more satisfactory program for clinical treatment of burn scars or post-operative linear scars.

Objective: To investigate the effect of 10,600 nm CO2 laser combined with the cold-air cooling device Zimmer Cryo 6 on the comfort and efficacy of patients with burn scars or post-operative linear scars, and to provide a safer, more effective and more satisfactory program for clinical treatment of burn scars or post-operative linear scars.

Secondary objective: To investigate the adverse effects of the cold-air cooling device Zimmer Cryo 6 in combination with the 10,600 nm CO2 fractional laser treatment for patients with burn scars or post-operative linear scars.

Inclusion Criteria:

1. Age 14-60 years;
2. The patient agreed to participate in the experiment and signed the informed consent by himself/herself or his/her legal representative;
3. The clinical diagnosis was burn scar or post-operative linear scar, and the total area was more than 5 cm2.
4. No other treatment such as laser or chemical exfoliation was performed on the lesion within the recent half year.
5. Skin lesions were free of bleeding, ulceration, infection and other conditions affecting the visual field of laser treatment.

Exclusion Criteria:

1. Patients with an active or established sun tan;
2. Patients with history of allergic reaction to to topical anesthesia;
3. Patients with history of keloid scarring, abnormal wound healing and/or prone to bruising;
4. Skin malignant tumors or precancerous lesions;
5. Patients with diabetes, heart disease, epilepsy, connective tissue disease, etc.;
6. Pregnant or breastfeeding patients;
7. Patients with recent skin infections (such as viral and bacterial infections);
8. Patients who are using other methods to treat similar diseases;
9. Patients who had taken isotretinoin within the past year;
10. History of cryoglobulinaemia;
11. History of cold agglutinin disease and cold haemolysis;
12. History of cold urticaria;
13. Parts of the body with impaired circulation;
14. Raynaud's disease;
15. Parts of the body with impaired sensitivity;
16. Trophic disorders;
17. Hypersensitivity to cold;
18. Patients with mental illness;
19. Other ineligible patients.